Work-clamping mechanism.



E. J. HAY.

WORK CLAMPING MECHANISM.

APPLICATION FILED OCT. 16. I916.

1,265,383. Patented May 7,1918.

3 SHEETS-SHEET I.

E. J. RAY.

WORK CLAMPING MECHANISM.

APPLICATION FILED OCT. I6, 1916.

Patented Ma 7, 1918.

*rn snares AENT ennren. 1

EUGENE J. BAY, OF BEVERLY, MASSACHUSETTS, ASSIGNOR, BY MESNEASSIGNMENTS,

TO UNITED SHOE MACHINERY CORPORATION, OF PATTERSON, NEW JERSEY, A COR-PORATION OF NEW JERSEY.

WORK-CLAMPIN G MECHANISM.

Specification of Letters Patent.

Patented May '3, 1918.

To all whom it may concern:

Be it known that I, EUGENE J. RAY, a citizen of the United States,residing at Beverly, in the county of Essex and State of Massachusetts,have invented certain new and useful Improvements in WVork-ClampingMechanism; and I do hereby declare the following to be a full, clear,and exact description of the invention, such as will enable othersskilled in the art to which it appertains to make and use the same.

The invention relates to mechanism for operating the work holding clampsof buttonhole sewing machines in which the clamp and sewing mechanismare relatively movable to form overseam stitches along the sides andabout the end or ends of the buttonhole.

The object of the invention is to provide novel and improved mechanismfor operating the two movable clamping members of the'work holder whichwill automatically equalize the pressure applied thereby to the work.

To this end the invention comprises the features of construction andcombinations of parts hereinafter described and set forth in the claims,the advantages of which will be apparent to those skilled in the artfrom the following detailed description of the preferred form of theinvention.

The invention will be readily understood from an inspection of theaccompanying drawings and the following detailed description of themechanism illustrated therein.

In the drawings, Figure 1 is a side elevation showing so much of abuttonhole sewing machine as is necessary to illustrate the applicationof the present improvements thereto; Fig. 2 is a plan view showing thework holding clamp; Fig. 3 is a side elevation of the clamp operatingmechanism; Fig. 4 is a sectional elevation on line 4-4, Fig. 2; andFigs. 5 and 6 are detail front and rear views of the clamp operatingrock shaft and parts carried thereby.

The invention is shown as embodied in a buttonhole sewing machine havingthe general construction and mode of operation of the machine shown anddescribed in Patent No. 1,063,880, June s, 1913.

In this machine the stitch-forming mechanism comprises an upper needle 2and 00- Fig. 1. The stitch-forming mechanism is rotated during thesewing about the eye and 7 end of the buttonhole as fully explained insaid patent.

The work holder comprises the lower clamping blocks 6, carried by thework supporting plates 8, and the cooperating upper clamping jaws 10,pivoted to the ends of the clamp carrying arms 12. The clamp carryingarms are pivotally supported in blocks 14, adjustably secured in thework supporting plates 8, and the arms are forced upward by springs 16.The work supporting plates 8 are pivotally supported upon a clampcarriage which is moved lengthwise of the buttonhole to move the workheld between the clamping members from cutting to sewing position at thebeginning of a buttonhole, and from sewing to cutting position at thecompletion of a buttonhole and is also moved longitudinally andlaterally to feed the work during the sewing.

At the beginning of the buttonhole making operation the buttonhole slitiscut by a cutter 18 carried on the forward end of a cutter lever 20,the rear end of which is arranged cutting toise'wing position, the worksupporting plates 8 are moved laterally or separated to spread theworkby a fixed spreading cam, indicated at 26 in Fig. 2.

In the construction shown the mechanism for closing the clamps andequalizing the pressure applied to the work by the two pairs ofcooperating clamping members comprises a rock shaft 28, mounted inbearings 30 in the clamp carriage, and carrying arms 32 which bear uponthe clamparms 12 and are so connected that theywill equalize thepressure transmitted through the rock shaft to the clamp arms. As shown,the arms 32 are formed on a rock lever 34 which is journaled on the rockshaft to turn about an axis at right angles to the axis of the rockshaft and substantially midway between the clamp arms. The equalizinglever 34 is provided with a journal 36, fitting within a bearing formedin a sleeve 38, which is secured to the rock shaft 28 by a set screw.40. Th

lever is retained within the bearing by a screw 42, the head of whichengages the rear end of the bearing. The equalizing'lever is heldyieldingly in mid position by a spring tobe engaged by a lug 52 on thecutter lever when the lever is rocked to cut the buttonhole slit. Aheavy spring 54 is interposed between a nut 56 on the screw and an arm58which projects upward from the sleeve 38 and is recessed to receiveand house the spring. The spring 54 normally holds the lever 48 againsta lug 60 on the arm 58, which projects back of the lever so that thelever, sleeve 38 and rock shaft 28 will rock in unison when the lever 48is operated by its engagement with the cutter lever, until movement ofthe clamp arms is arrested by the engagement of the clamps with thework, after which the lever 48 may have a slight independent forwardmovement to compress the spring 54 and through it to apply the properpressure to the work. Should the work be somewhat thicker on one side ofthe buttonhole than on the other, the equalizing lever may rock toaccommodate itself to the unequal downward movement of the clamp armsand to apply an equal pressure to both arms, whatever their verticalpositions. The pressure applied to the work by each pair of clampingmembers will be measured by the spring 54 which may be adjusted inaccordance with the character of the work being done, The work will,therefore, be uniformly and properly clamped, and in case the clampingmembers are separated to spread the work, the two pairs. of clampingmembers will exert the same spreading strain.

When the lever 48 is operative to close the clamp it is. locked in clampclosing position by a latch 62, arrangedto engage the upper c-ndlofthelever and provided with an arm 64, arranged to engage a dog 66' on themachine. frame. The dog 66 is so supported on the-frame that it willswing out of the path of, the. arm 64 during the forward movement of theclamp carriage but will depress the arm and raise; the latch 62 torelease and open the: clamp as the clamp/carriage completesits rearwardmovement after the buttonh-ole has been completed. A coiled spring .68acts on the latch 62 and on the lever 48 to; force the latch intolatching position and to-forcethelever in a direction to open the clampswhen thelatchis disengaged from the le er- While it is preferred tovemploy the specific construction and arrangement of parts clamp.

shown and described, especially in embodying the invention in themachine of the patent above referred to, it will be understood that thisconstruction and arrangement is not essential to the broader features ofthe invention but may be varied or modified as found desirable or bestsuited to the construction, and arrangement of thecooperatingparts andmechanisms of the machine in which it is to be embodied.

Having explained the nature and object of the invention, andspecifically described one form of mechanism in which it may beembodied, what is claimed is:

l. A buttonhole sewing machine, having, in combination, stitch-formingmechanism, a work clamp comprising two clamping members, mechanism forautomatically closing the clamping members and equalizing the pressureapplied thereby to the work atthe beginning of a buttonhole, andmechanism for automatically opening the clamping members at thecompletion of the buttonhole.

2. A buttonhole sewing machine, having, in combination, stitch-formingmechanism, a work clamp comprising two vertically movable clamp arms,two arms engaging the clamp arms and connected to equalize the pressureof the clamps on the work, and

mechanism for automatically operating the,

equalizing arms to cause the closing and opening of the clamp.

3. A buttonhole sewing machine, having, in combination, stitch-formingmechanism, a work clamp comprising two work'supporting plates laterallymovable to spread the work, two cooperating clamp arms mounted to movewith the corresponding plates, two arms engaging the clamp arms andconnected to equalize the pressure of the clamps on the work, andmechanism for operating the equalizing arms to close the 4. A buttonholesewing machine, having, in combination, stitch-forming mechanism, a workclamp comprising two pairs of work clamping members laterally movable tospread the work, and mechanism for automatically closing the clampingmembers and equalizing the pressure applied thereby to the work.

5. A buttonhole sewingmachine, having, in combination, stitch-forming,mechanism, a work clamp comprising two clamp arms, a rock shaft, anequalizing lever mounted on the rock shaft and provided with armsengaging the clamp arms, and operating mechanism for the rock shaftincluding a spring through which pressure, is transmitted to the rockshaft. 7

6. A buttonhole sewing machine, having, in combination, stitch-formingmechanism, a work clamp comprising two. 0121,1111) arms, a rock shaft,an equalizing lever journaled a rock shaft, an equalizing leverjournaled upon the rock shaft between the clamp arms 1 and provided witharms engaging the clamp arms, a lever for operating the rock shaft, anda spring between the lever and rock shaft through Which pressure isapplied to the clamp.

EUGENE J. RAY.

on the rock shaft to turn about an axis at right angles thereto andprovided with arms engaging the clamp arms, and mechanism for operatingthe rock shaft to cause the opening and closing of the clamps.

7. A buttonhole sewing machine, having, in combination, stitch-formingmechanism, a WOIk clamp comprising tWo clamp arms,

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents. Washington, D. C.

